1. Field of the Invention
The present invention relates to packaging substrates and methods of fabricating the same, and, more particularly, to a packaging substrate having an antenna and a method of fabricating the packaging substrate.
2. Description of Related Art
Along with the trends of low profile and compact size, a system in package (SiP) comes to the market. The SiP integrates various electronic elements, such as one or more chips, passive components, antennas, into the same package. If electromagnetic element working in high frequency, such as radio frequency (RF) element and antenna, are integrated into a high frequency device, the high-frequency device will interfere the operation of neighboring electronic element. To meet the high integration requirement, electronic elements in the package are disposed closer and closer, which worsens the interference problem.
Thus, electromagnetic interference becomes one of the major issues in designing a wireless communication module and an antenna, such as a global system for mobile communication (GSM), a wireless LAN (WLAN), a global positioning system (GPS), a Bluetooth apparatus, and a digital video broadcasting-handheld (DVB-H) apparatus. The wireless modules and antennas are integrated in a limited area, and the noise generated by the devices will affect each other. Thus, the design of integrating the high frequency modules and shielding the other devices from noises are the important factors in packing design.
U.S. Pat. No. 7,049,682 discloses a packing structure with integral shield and antenna. Referring to FIGS. 1A and 1B, a method of fabricating a packaging structure according to the prior art.
As shown in FIG. 1A, a package 1a and a cover 1b are provided. The package 1a has a substrate 10 and a plurality of packaging elements 11 and 12 separated from each other at a predetermined interval on the substrate 10. The packaging elements 11 and 12 have electronic elements 110 and 120, respectively, that are electrically connected to the substrate 10. The cover 1b has a dielectric covering element 14, shields 13 disposed on an internal surface of the dielectric covering element 14 and corresponding to the packaging elements 11 and 12, and an antenna 16 disposed on an external surface of the dielectric covering element 14.
As shown in FIG. 1B, an adhesive material 15 adheres the cover 1b to the substrate 10, such that the shields 13 cover the packaging elements 11 and 12 from electromagnetic interference.
In the packaging structure according to the prior art, the cover 1b that is integrated with a shield structure (e.g., the shield 13) and the antenna 16 is adhered to the package 1a, in order to eliminate the electromagnetic interference.
However, in the cover 1b of the packaging structure according to the prior art, the shields 13 have to correspond in position to the packaging elements 11 and 12. Therefore, the cover 1b shall be re-designed if it is used to cover the packaging elements 11 and 12 that have different layout or to cover more than two packaging elements.
Moreover, gaps, such as an upper space h and a peripheral space w, as shown in FIG. 1B, exist between the shield 13 and the packaging elements 11 and 12. Accordingly, the substrate 10 has to have an increased size and the packaging structure has an increased height, resulting in an adverse effect to the requirements of low profile and compact size.
In addition, the cover lb has too thick a dielectric cover 14, which is also against the miniaturization of the packaging structure.
Therefore, how to overcome the problems of the prior art becomes a critical topic.